package com.flym.hrdh.utils;

/**
 * <p>Title:红人带货系统</p>
 * <p>Description:RC4加密管理</p>
 * <p>Copyright: Copyright (c) 2020-04-28</p>
 * <p>Company: 翔梦[http://mail.flym.cn]</p>
 * @author $Author: jh.x $
 * @version $Revision: 1.0.0 $
 */
public class RC4 {

        public static String decry_RC4(byte[] data, String key) {
            if (data == null || key == null) {
                return null;
            }
            return asString(RC4Base(data, key));
        }

        public static String decry_RC4(String data, String key) {
            if (data == null || key == null) {
                return null;
            }
            return new String(RC4Base(HexString2Bytes(data), key));
        }

        public static byte[] encry_RC4_byte(String data, String key) {
            if (data == null || key == null) {
                return null;
            }
            byte b_data[] = data.getBytes();
            return RC4Base(b_data, key);
        }

        public static String encry_RC4_string(String data, String key) {
            if (data == null || key == null) {
                return null;
            }
            return toHexString(asString(encry_RC4_byte(data, key)));
        }

        private static String asString(byte[] buf) {
            StringBuffer strbuf = new StringBuffer(buf.length);
            for (int i = 0; i < buf.length; i++) {
                strbuf.append((char) buf[i]);
            }
            return strbuf.toString();
        }

        private static byte[] initKey(String aKey) {
            byte[] b_key = aKey.getBytes();
            byte state[] = new byte[256];

            for (int i = 0; i < 256; i++) {
                state[i] = (byte) i;
            }
            int index1 = 0;
            int index2 = 0;
            if (b_key == null || b_key.length == 0) {
                return null;
            }
            for (int i = 0; i < 256; i++) {
                index2 = ((b_key[index1] & 0xff) + (state[i] & 0xff) + index2) & 0xff;
                byte tmp = state[i];
                state[i] = state[index2];
                state[index2] = tmp;
                index1 = (index1 + 1) % b_key.length;
            }
            return state;
        }

        private static String toHexString(String s) {
            String str = "";
            for (int i = 0; i < s.length(); i++) {
                int ch = (int) s.charAt(i);
                String s4 = Integer.toHexString(ch & 0xFF);
                if (s4.length() == 1) {
                    s4 = '0' + s4;
                }
                str = str + s4;
            }
            return str;// 0x表示十六进制
        }

        private static byte[] HexString2Bytes(String src) {
            int size = src.length();
            byte[] ret = new byte[size / 2];
            byte[] tmp = src.getBytes();
            for (int i = 0; i < size / 2; i++) {
                ret[i] = uniteBytes(tmp[i * 2], tmp[i * 2 + 1]);
            }
            return ret;
        }

        private static byte uniteBytes(byte src0, byte src1) {
            char _b0 = (char) Byte.decode("0x" + new String(new byte[] { src0 })).byteValue();
            _b0 = (char) (_b0 << 4);
            char _b1 = (char) Byte.decode("0x" + new String(new byte[] { src1 })).byteValue();
            byte ret = (byte) (_b0 ^ _b1);
            return ret;
        }

        private static byte[] RC4Base(byte[] input, String mKkey) {
            int x = 0;
            int y = 0;
            byte key[] = initKey(mKkey);
            int xorIndex;
            byte[] result = new byte[input.length];

            for (int i = 0; i < input.length; i++) {
                x = (x + 1) & 0xff;
                y = ((key[x] & 0xff) + y) & 0xff;
                byte tmp = key[x];
                key[x] = key[y];
                key[y] = tmp;
                xorIndex = ((key[x] & 0xff) + (key[y] & 0xff)) & 0xff;
                result[i] = (byte) (input[i] ^ key[xorIndex]);
            }
            return result;
        }

        public static void main(String[] args) {
            String inputStr = "做个好男人";
            String str = encry_RC4_string(inputStr, "123456");
            System.out.println(str);
            System.out.println(decry_RC4(str, "123456"));
        }

}
